使用实体框架TPT的多个继承级别

Question

Considering the following table schema:

I want to use Entity Framework Table-Per-Type (Fluent API) to map to the following class diagram:

How can I do this? I have tried doing it like the examples at the Microsoft site but looks like no example covers a two-depth inheritance scenario and I get errors related to invalid discriminator columns and so on. I am using one EntityTypeConfiguration per type. How can I specify the name of the foreign key cascading down children?

If anyone has an example of how to do such mapping, I would be grateful forever.

Thanks!

Answer 1

So your table per type won't quite work for your schema because table per type links tables together through a shared primary key. You could modify your schema so that UserAccounts, ExternalUserAccounts, and SystemUserAccounts are all keyed on UserAccountId. Then the code below is close to what you want. Otherwise, you'll want to use regular association properites.

Read about table per type here and shared primary keys here .

    public class UserAccount
    {
        public int UserAccountId {get;set;}
        public int UserId {get;set;}
        public DateTime LastLogin {get;set;}
        public bool IsLocked {get;set;}
        public bool IsActive {get;set;}
        public User User {get;set;}
    }

    public class ExternalUserAccount : UserAccount
    {
        public int ExternalAccountId {get;set;}
        public string ProviderName {get;set;}
        public string ProviderUserName {get;set;}
    }

    public class SystemUserAccount : UserAccount
    {
        public int SystemUserAccountId {get;set;}
        public string PasswordHash {get;set;}
        public string Token {get;set;}
    }

    public class User
    {
        public int UserId {get;set;}
        public string Name {get;set;}
        public string Description {get;set;}
    }

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<UserAccount>().ToTable("UserAccounts");
        modelBuilder.Entity<UserAccount>().HasKey(ua => ua.UserAccountId);
        modelBuilder.Entity<UserAccount>().HasRequired(ua => ua.User)
                                          .WithMany()
                                          .HasForeignKey(ua => ua.UserId);
        modelBuilder.Entity<ExternalUserAccount>().ToTable("ExternalUserAccounts");
        modelBuilder.Entity<SystemUserAccount>().ToTable("SystemUserAccounts");
        modelBuilder.Entity<User>().ToTable("Users");
        modelBuilder.Entity<User>().HasKey(u => u.UserId);

    }